High Voltage Forum

Tesla coils => Solid state Tesla coils => Topic started by: Platinum on January 24, 2019, 05:29:44 PM

Title: SGTC secondary used in SSTC mode?
Post by: Platinum on January 24, 2019, 05:29:44 PM
Hello HVF, recently I made a secondary coil using 110mmOD drain pipe, 0.24mm wire with about 1200 turns, height diameter ratio is about 1-4 as I originally intended to use it as a medium sized SGTC of around 3kw. Now I'd like to use it in solid state mode and was wondering if I could use it at all and would I run into any problems?

Also as a additional question is there any decent full bridge driver I could buy as I'm struggling for time to build one as I have a newborn daughter

Thanks in advance

Title: Re: SGTC secondary used in SSTC mode?
Post by: Hydron on January 24, 2019, 05:43:25 PM
Sounds like a reasonable secondary for a (DR)SSTC - you'll want to use reasonable fast IGBTs as it I estimate will resonate around 200-250kHz with a sensible size topload, but good TO-247 IGBTs should handle it OK (try FGY75N60SMD/FGA60N65SMD/FGH60N60SMD). There are some designs in this forum which could get you started with a full bridge PCB (order from a cheap chinese PCB house), and for a driver you could again use a design found here or get something off ebay/aliexpress (again, check the forum for reviews and options).

As you didn't mention having a toroid already, as an option I am happily using one of these with a secondary of the same 110mm diameter: https://www.ebay.co.uk/itm/Spun-Aluminium-Toroid-for-Tesla-Coil-HV-High-Voltage-300mm-by-75mm/113538948995
For that price it's not worth trying to DIY one! (Note comes in 2 halves, to hold it together either use the mounting bolt or roughen up the flat area on the inside and epoxy together).
Title: Re: SGTC secondary used in SSTC mode?
Post by: Platinum on January 24, 2019, 08:24:49 PM
Sounds like a reasonable secondary for a (DR)SSTC - you'll want to use reasonable fast IGBTs as it I estimate will resonate around 200-250kHz with a sensible size topload, but good TO-247 IGBTs should handle it OK (try FGY75N60SMD/FGA60N65SMD/FGH60N60SMD). There are some designs in this forum which could get you started with a full bridge PCB (order from a cheap chinese PCB house), and for a driver you could again use a design found here or get something off ebay/aliexpress (again, check the forum for reviews and options).

As you didn't mention having a toroid already, as an option I am happily using one of these with a secondary of the same 110mm diameter: https://www.ebay.co.uk/itm/Spun-Aluminium-Toroid-for-Tesla-Coil-HV-High-Voltage-300mm-by-75mm/113538948995
For that price it's not worth trying to DIY one! (Note comes in 2 halves, to hold it together either use the mounting bolt or roughen up the flat area on the inside and epoxy together).


Hi Hydron, thank you for the detailed and helpful reply, if I remember from JavaTC inputs the Fres was about 234khz, I have some spare 60H60 trench gate field stop IGBTs leftover from another full bridge build I done which is used to power a homemade flyback, I have had a look at the Chinese drivers but I am struggling to come to conclusion which one would be most appropriate as all the descriptions are meaningless to me, if I post a few could you help me make a decision?

As for the toroid, luckily I work in engineering and could have one made to spec for free, thanks for the heads up though.

Thank you 👍